Objective To observe the pathological changes of hippocampus and myelin in rats with frontal cereberal ischemia and reperfusion after treated with methylcobalamine and to discuss the mechanism of the cerebral protective effect of methylcobalamine.Methods Cerebral ischemia and reperfusion models were made by clamping bilateral carotid arteries.Forty-five male Wistar rats were randomly allocated to sham-operation group,ischemia-reperfusion group and methylcobalamine group(n=15).1,2,4 weeks after reperfusion the rats in each group were divided into three groups(n=5).The pathological changes of hippocampus and myelin were observed by using light microscope,HE staining,LFB staining and electron microscope.Results The pyramidal neurons in hippocampus in ischemia and reperfusion groups expressed putrescence and myelin necrosis or demyelination at 1st week,and the histomorphological changes at 4th week were significant than that at 2nd week.The followings were observed in electron microscope: dimness,partly solubilization and collapsablity in myelin.The pyramidal neurons in hippocampus of therapy groups were similar to normal one and myelin expressed compaction and shipshape.The changes were more obvious at 4th week.Conclusion Methylcobalamine can obviously decrease the ischemia lesion of hippocampus and myelin and protect the brain function.

Objective To explore the regulatory mechanism of the interaction between trigeminal ganglion neurons and satellite glial cells （SGCs） in migraine and to identify key factors mediating this interaction. Methods The trigeminal ganglia of eight 2-to 3-day-old Wistar rats were cultured in vitro for 3 days. A migraine cell model was established using sensory nerve action potential （SNAP） with nitric oxide （NO） donor. The in vitro migraine simulation group was treated with SNAP at concentrations of 0.25 mmol/L， 0.5 mmol/L， and 1 mmol/L for 2 hours. The inhibitor group received intervention with AR-A014418 （10 μmol/L）， followed by SNAP （1 mmol/L） 30 min later， allowing for 2 hour intervention. The intervention-free group served as a control. The levels of calcitonin gene-related peptide （CGRP）， substance P（SP）， and prostaglandin E2 （PGE2） in the cultured cells from each group were measured using enzyme-linked immunosorbent assay （ELISA）. The positive and negative regulatory sites of glycogen synthase kinase-3β （GSK-3β） and the changes in the expression of CX3CL1/CX3CR1 proteins were evaluated using immunofluorescence assay. The expression of GSK-3β and CX3CL1/CX3CR1 was semi-quantitatively analyzed using Western blotting. Results The expression levels of CGRP， PGE2， and SP in the SNAP （1 mmol/L） group were significantly higher than those in the control group， while the expression levels in the inhibitor group was significantly lower than those in the SNAP （1 mmol/L） group （both P<0.05）. Immunofluorescence assay showed that the SNAP （1 mmol/L） group exhibited decreased expression of pGSK-3β Ser9 and increased expression of GSK-3β Try216 and CX3CL1/CX3CR1 in trigeminal ganglion cells when compared with the control group. In contrast， the inhibitor group exhibited increased expression of pGSK-3β Ser9 and decreased expression of pGSK-3β Try216 and CX3CL1/CX3CR1 when compared with the SNAP （1 mmol/L） group. Conclusion NO enhances the expression of GSK-3β in trigeminal ganglia， up-regulates CX3CL1/CX3CR1， and activates SGCs to produce inflammatory factors. This signaling pathway represents a regulatory mechanism of the development and progression of migraine.